RHSA-2012:1540 - Security Advisory

Synopsis

Type/Severity

Security Advisory: Important

Topic

Updated kernel packages that fix multiple security issues, two bugs, andadd two enhancements are now available for Red Hat Enterprise Linux 5.

The Red Hat Security Response Team has rated this update as havingimportant security impact. Common Vulnerability Scoring System (CVSS) basescores, which give detailed severity ratings, are available for eachvulnerability from the CVE links in the References section.

Description

These packages contain the Linux kernel.

Security fixes:

A race condition in the way asynchronous I/O and fallocate() interactedwhen using ext4 could allow a local, unprivileged user to obtain randomdata from a deleted file. (CVE-2012-4508, Important)

A flaw in the way the Xen hypervisor implementation range checked guestprovided addresses in the XENMEM_exchange hypercall could allow amalicious, para-virtualized guest administrator to crash the hypervisor or,potentially, escalate their privileges, allowing them to execute arbitrarycode at the hypervisor level. (CVE-2012-5513, Important)

A flaw in the Reliable Datagram Sockets (RDS) protocol implementationcould allow a local, unprivileged user to cause a denial of service.(CVE-2012-2372, Moderate)

A race condition in the way access to inet->opt ip_options wassynchronized in the Linux kernel's TCP/IP protocol suite implementation.Depending on the network facing applications running on the system, aremote attacker could possibly trigger this flaw to cause a denial ofservice. A local, unprivileged user could use this flaw to cause a denialof service regardless of the applications the system runs. (CVE-2012-3552,Moderate)

The Xen hypervisor implementation did not properly restrict the periodvalues used to initialize per VCPU periodic timers. A privileged guest usercould cause an infinite loop on the physical CPU. If the watchdog wereenabled, it would detect said loop and panic the host system.(CVE-2012-4535, Moderate)

A flaw in the way the Xen hypervisor implementation handledset_p2m_entry() error conditions could allow a privileged,fully-virtualized guest user to crash the hypervisor. (CVE-2012-4537,Moderate)

Red Hat would like to thank Theodore Ts'o for reporting CVE-2012-4508; theXen project for reporting CVE-2012-5513, CVE-2012-4535, and CVE-2012-4537;and Hafid Lin for reporting CVE-2012-3552. Upstream acknowledges DmitryMonakhov as the original reporter of CVE-2012-4508. CVE-2012-2372 wasdiscovered by Li Honggang of Red Hat.

Bug fixes:

Previously, the interrupt handlers of the qla2xxx driver could clearpending interrupts right after the IRQ lines were attached during systemstart-up. Consequently, the kernel could miss the interrupt that reportedcompletion of the link initialization, and the qla2xxx driver then failedto detect all attached LUNs. With this update, the qla2xxx driver has beenmodified to no longer clear interrupt bits after attaching the IRQ lines.The driver now correctly detects all attached LUNs as expected. (BZ#870118)

The Ethernet channel bonding driver reported the MII (Media IndependentInterface) status of the bond interface in 802.3ad mode as being up eventhough the MII status of all of the slave devices was down. This could posea problem if the MII status of the bond interface was used to determine iffailover should occur. With this update, the agg_device_up() function hasbeen added to the bonding driver, which allows the driver to report thelink status of the bond interface correctly, that is, down when all of itsslaves are down, in the 802.3ad mode. (BZ#877943)

Enhancements:

This update backports several changes from the latest upstream version ofthe bnx2x driver. The most important change, the remote-fault linkdetection feature, allows the driver to periodically scan the physical linklayer for remote faults. If the physical link appears to be up and a faultis detected, the driver indicates that the link is down. When the fault iscleared, the driver indicates that the link is up again. (BZ#870120)

The INET socket interface has been modified to send a warning messagewhen the ip_options structure is allocated directly by a third-party moduleusing the kmalloc() function. (BZ#874973)

Users should upgrade to these updated packages, which contain backportedpatches to correct these issues and add these enhancements. The system mustbe rebooted for this update to take effect.

Solution

Before applying this update, make sure all previously-released erratarelevant to your system have been applied.

This update is available via the Red Hat Network. Details on how touse the Red Hat Network to apply this update are available athttps://access.redhat.com/knowledge/articles/11258

To install kernel packages manually, use "rpm -ivh [package]". Do notuse "rpm -Uvh" as that will remove the running kernel binaries fromyour system. You may use "rpm -e" to remove old kernels afterdetermining that the new kernel functions properly on your system.